Eye axial length is a primary issue for judging eye ametropia. It is also an important indication for discriminating true myopia and pseudomyopia, and for computing parameters of an artificial crystal for a cataract operation.
In existing art, methods for measuring an eye axial length include A-scan ultrasonic measurement and optical measurement. Existing A-scan ultrasonic measurement takes advantage of ultrasonic ranging principle. However, it is necessary to directly touch human eye with a probe in the A-scan ultrasonic measurement. Moreover, resolution of A-scan ultrasonic measurement is relatively low and thus is incapable of measurement with a sufficient accuracy. In optical measurement, an eye axis length is measured based on the theory of dual-wavelength light wave interference. Optical Coherence Tomography (OCT) is a newly developing optical imaging technique. Patent CN200710020707.9 discloses a method of measuring an eye axial length with OCT, and eye axial length measurement for human eye and eyes of various kinds of living animals can be implemented with this method. However, the inventor, during the practice of the invention, discovered that the existing art at least has the following disadvantages. Firstly, the optical path is adjusted by using a movable probe moved by a stepping motor to realize imaging of the cornea and fundus. It takes a certain time for the motor to move back and forth. Thus, it is incapable of quickly switching between the anterior and posterior eye segments and realizing real-time imaging. Furthermore, since the measured object will shake its eyes, the measurement of eye axial length is inaccurate with a large error. Secondly, the imaging quality is bad due to the fact that the cornea and fundus have different shapes and it is unable for a single probe to focus at both of the two locations.